Introduction to animals Introduction to Animals

Traits

Characteristics of Animals All multicellular (metazoans) Eukaryotes (cells with nucleus & organelles) Ingestive heterotrophs (take in food and internally digest it) Store food reserves in the liver as glycogen

Lions Feeding (Ingestion)

Support Systems Have some type of skeletal support Endoskeleton inside and made of cartilage &/or bone Exoskeletons found in arthropods –Cover the outside of the body –Limit size –Must be molted making animal vulnerable to predators

Cicada Molting Exoskeleton

Support Systems Worms and echinoderms (starfish) have fluid-filled internal cavities giving them support Called hydrostatic skeletons

Movement Animals such as sponges may be sessile (attached & non-moving) Animals that move very little are said to be sedentary (clam) Animals that can move are motile Have muscular tissue to provide energy for movement

SESSILESEDENTARY MOTILE Sponge Chiton Cheetah

Reproduction in Animals sexual reproduction Some like sponges and earthworms are hermaphrodites produce eggs and sperm may exchange sperm and NOT fertilize their own eggs

Leeches Exchange Sperm During Mating Mating leech

Reproduction in Animals Females of some animals produce eggs, but the eggs develop without being fertilized Called Parthenogenesis New offspring will be all female occurs in some fishes, several insects, and frogs and lizards

Parthenogenesis in the Komodo Dragon

Mating and Mating Behaviors Beetles Mating Male Female Young Courtship

Levels of Organization Sponges =ONLY animals with just cellular level All others show– cell, tissue, organ, and system Cells may specialize (take own different shapes and functions) Cells held together by cell junctions to form tissues

Atom Molecule or compound Organelle CELL Levels of Organization Tissue Organ Organ system Organism Life begins

Invertebrate groups

Characteristics of Invertebrates Simplest animals greatest number of different species Most aquatic (found in water) NO backbone Includes sponges, cnidarians, flatworms, roundworms, annelids, mollusks, arthropods, and echinoderms

Sponge - Porifera Osculum of Sponge

20 Sponges and Cnidarians

Sea Anemone - Cnidaria Tentacles of Sea Anemone

More Cnidarians Brain Coral Red jellyfish

23

Flatworms - Platyhelminthes Planarian Marine Flatworm

Roundworms (Nematoda) and Segmented Worms (Annelida) Nematode Leech (segmented worm)

Mollusca (With and Without Shells) snailscallop nautilus sea slug octopus

Arthropoda (insects, spiders, crustaceans, horseshoe crab) Dung beetle Horseshoe crab crayfish spider

Echinoderms Sea cucumber Sand dollar starfish Brittle star Sea fan (crinoid)

Vertebrate Groups (Phylum Chordata, Subphylum Vertebrata)

Vertebrata More complex backbone of vertebrae simplest phylum to most complex: fish, amphibians, reptiles, birds, and mammals

Vertebrate Backbone

Vertebrata endoskeletons (internal) Some have skeletons of cartilage (sharks, rays, and skates)

Bone & Cartilage in Fetus

Fish lancelet ray anglerfish damselfish

Amphibia toad newt frog salamander

Reptilia Turtle Snake Alligator Lizard

37 Reptiles

Birds - Aves hummingbird ostrich lovebirds

Mammalia

Body Areas

Surfaces Dorsal – back Ventral – belly Anterior –front end Posterior –hind end Oral surface–mouth Aboral surface–opposite the mouth

DORSAL VENTRAL Surfaces (Most Animals) ANTERIOR POSTERIOR

Surfaces (Echinoderms) ORAL ABORAL mouth

Symmetry

Body Symmetry

Symmetry = arrangement of body parts around central axis Asymmetry

Body Symmetry Radial symmetry = body parts arranged around central point like spokes (echinoderms) –Most with radial symmetry are sessile (attached) or sedentary (move very little)

Body Symmetry Bilateral symmetry = divided into equal halves right and left sides are mirror images More complex

Body Symmetry bilateral symmetry, usually motile anterior and posterior ends Show cephalization concentration of sensory organs on the head

Segmentation

Segmentation Earthworms show external segmentation Humans show internal segmentation (backbone) Segments may fuse (cephalothorax)

Segmentation cephalothorax

Tissues

Tissue Development Zygote (fertilized egg) undergoes rapid cell divisions =cleavage Forms a hollow ball of cells =blastula

Blastula The blastocoel = center cavity of blastula with 1 germ layer (blastoderm)

Tissue Development folds inward at one point =Gastrulation opening =blastopore blastopore Archenteron

Tissue Development Blastopore may become mouth (Protostome) or anus (Deuterostome) Protostomes (mollusks, arthropods, & annelids) Deuterostomes (echinoderms & vertebrates) Some animals form a middle germ layer called mesoderm

Embryonic Development

Germ Layers NOT present in sponges Ectoderm (outer) – forms skin, nerves, sense organs Endoderm (inner) – forms liver and lungs Mesoderm (middle) – forms muscles & other systems

Body Layers All worms, mollusks, arthropods, echinoderms, and vertebrates have three cell layers –Ectoderm –Endoderm –mesoderm

Stages of Development

Larval Forms Animals with Indirect development Larva does NOT resemble adult Cnidarian larva = Planula

Larval Forms Mollusk (squid & octopus) larva = trochophore Echinoderm (starfish) larva is = Dipleurula

Metamorphosis Usually found in arthropods May be complete or incomplete Incomplete Metamorphosis: egg nymph adult Complete Metamorphosis: egg larva pupa adult

Metamorphosis COMPLETE INCOMPLETE

Body Cavities

Coelom - Body Cavity Internal body cavity fully lined with mesoderm Body organs suspended in this cavity

Coelom - Body Cavity Acoelomate =solid bodies filled with cells Ex.sponges, cnidarians, & flatworms

Coelom - Body Cavity Pseudocoelomate = (roundworms) = functional body cavity NOT fully lined with mesoderm

Animal Systems

Support Systems Spongin & spicules (sponges) Limestone cases (corals) Exoskeletons of Chitin (arthropods) –Must be shed or molted to grow Inner Calcium plates (echinoderms) Bone/cartilage endoskeleton (vertebrates)

Digestive Systems All animals = ingestive heterotrophs Gastrovascular cavity with one opening in cnidarians & flatworms = two-way digestive system

Two-Way Digestion

Digestive Systems one-way digestive system = mouth and an anus Includes annelids, arthropods, & vertebrates

One-Way Digestion Mouth anus

Circulatory Systems Transports oxygen & nutrients to cells Carries away wastes & carbon dioxide from cells Sponges, cnidarians, & flatworms do NOT have circulatory systems

Circulatory Systems In closed circulation, blood remains inside blood vessels until it reaches cells (annelids & vertebrates) In open circulation, blood is pumped out of blood vessels to bathe tissues in the body cavity or hemocoel (arthropods & mollusks)

Open Circulation Closed Circulation